Grapevine pest

Trish starts with ... Ok, so I have these bug-things on my grapevine and I can't work out what they are. I've had a couple of suggestions but if anyone knows for sure, can they please let me know.

They kind of look like limpets when I turn them over. Flat and wet. They range in colour from milky clear to brown to black. They are on both sides of the leaves and the stems and the trunks. There are also ants on the vine. They may be scale.

Will they invade other plants? I have vegies and citrus and mulberry. How and when do I kill them. Winter has just started here.

It's Scale. When young they have a milky colour but the hard shell turn black when they get old. This armor to protect them hidden underneath. They thrive in the warm and dry atmosphere. To get rid of them there are many ways but you need to spay tap water first to soften the armor as the spore expanded when contacted with water. See the link below for more info. The more costly and lazy way is to spray with Rubbing Alcohol ratio 1:1 and repeat few times. Cheers

Something else that came to mind.
Like you said, winter is here. Grapes will soon drop all their leaves.
Cut the leaves off now, bag them in oven bags, bring them inside, add some water, loosely tie the bag (so it wont explode), put it in a microwave proof bowl and boil them for a couple of minutes. Dispose of dead unwanteds.
The obvious ones can simply be removed and squished, but removing the entire leaf (it's going to drop anyway) and bagging it gets everything on it, and easily.

If the leaves are left to drop in your garden, the scale will drop with them.
Once scale mature to their form when they produce their 'scale' they never move again. They are the female. The male comes in, does its thing, and is spent ... adios old boy!
The female then produces what they call 'crawlers' that move on looking for a place to repeat the process. The 'crawlers' are more susceptible to spray treatment, as they aren't protected by a 'shell'.
Point is, letting them drop onto the soil, allows any 'crawlers' (and potential 'crawlers') to wander around looking for a close by plant to climb (very similar to the way ticks on cattle work). Now is the ideal time to grab the grape vine's leaves before they fall.

If your vine is in a pot, move it onto the drive-way or somewhere to do the work. Wrap some cling film around the base of the vine and cover the soil in the pot. Defoliate and bag the leaves. Brush off the ones attached to shoots and catch on a sheet of paper or something (a white sheet helps to see your 'catch', and the cling film is just a back-up and can be removed later).

Once the vine is 'clean' a preventative spray to try to intercept any 'crawlers' wouldn't hurt. I haven't tried this myself, but have read that soapy water smothers and suffocates lace, which I'd guess to do the same for juvenile scale. Soapy (bar of soap, not detergent) dries into that soap scum you get in the bathroom, which encases, and suffocates the pest.

Rain will wash the soap from the plant and into the soil. Soap is alkaline, so I'll leave it up to everyone else to ponder the pros and cons of different chemicals and remedies. Soap is just a suggestion that I've never tried.

And yes, I've knocked off quite a bit of scale (same as the one in your picture) from citrus. I've only done the manual labour though. I don't spray anything.

I completely ridded a Matisia of aphids and lace with the method explained above (although I did go extreme by removing all the soil, sterilising it in an oven, and repotting). Didn't use the soap spray though.